A projector provided with charge-coupled devices (CCD) within an optical system has been proposed. When a position is indicated on a screen using a laser pointer during the projection of an image on the screen, the laser light is reflected by the screen, travels in a direction opposite to that of the projected light, and enters the optical system of the projector. In such projectors, the CCD detects the laser light so that the indicated position on the screen can be determined.
For example, a window area, having items such as screen frame forward, frame back, etc., can be displayed along with an internet page or an image photographed with a digital camera. When a desired item is specified by the laser pointer, the specified position on the screen is detected by the projector, and a corresponding frame forward or frame back operation is performed. Further, not only can detecting a specified position trigger an operation, it is also possible to fetch an image corresponding to an area specified by the laser pointer.
When using an area CCD as a photosensing means in a conventional projector, the detection area of the reflected light extends over the entire screen, and extensive data processing is required for detection when an area CCD is used. Furthermore, an area CCD is expensive an adds an unnecessary cost to the device.
The laser pointers conventionally used for indicating a position on a screen illuminate the screen with the laser light. Since laser light is harmful when it enters the human eye, extreme care must be taken by anyone using a laser pointer so that the laser light does not stray off the screen inadvertently.